In the first version of the Java Concurrency API, you had to create and run all the threads of your application. In Java version 5, with the appearance of the Executor framework, a new mechanism was introduced for the execution of concurrency tasks.

With the Executor framework, you only have to implement your tasks and send them to the executor. The executor is responsible for the creation and execution of the threads that execute your tasks.

Internally, an executor uses a blocking queue to store pending tasks. These are stored in the order of their arrival at the executor. One possible alternative is to use a priority queue to store new tasks. This way, if a new task with high priority arrives to the executor, it will be executed before all the other threads that have already been waiting but have comparatively lower priority.

In this recipe, you will learn how to adapt an executor that will use a priority queue to store the tasks you send for execution.